The U.S. government moved to impose substantial punitive tariffs on hundreds of millions of dollars of imported steel products from South Korea and eight other countries, a much-anticipated decision that marks one of the largest anti-dumping cases in recent memory.

Steel imports from the nine countries may be hit with tariffs up to 118%, but the lion's share in this case — from South Korea — was targeted for levies with much smaller duties of 10% to 16%.

In the short term, the tariffs, if finalized, are expected to curb steel imports and lift U.S. prices of certain steel goods, which could be felt by American businesses and consumers.

The tariffs also may help restore several hundred steel factory jobs idled because of pressures from imports and probably will embolden domestic steel makers to file more claims of unfair pricing against foreign shippers.

But any relief to domestic steel manufacturers will be short-lived, analysts said.

Underlying the new threat to the U.S. steel industry are fundamental challenges in a global economy adjusting to a worldwide glut of steel, China's slowing demand and the uncertainties of America's shale gas boom.

We have this energy boom, we should be making all kinds of money.— Cliff Tobey, a third-generation miner in northeast Minnesota's Iron Range

The nation's energy revolution was supposed to be a godsend for the domestic steel business and its long-beleaguered workers, thanks to soaring orders from the oil and gas industry for specialized steel pipes and tubes needed for drilling and other purposes.

"We have this energy boom, we should be making all kinds of money," said Cliff Tobey, 40, a third-generation miner in northeast Minnesota's Iron Range, the source of most of the taconite for steel made in the U.S.

Instead, Tobey and thousands of other steel workers across the nation are worried about their job security. They have held rallies in recent weeks to call on federal officials to slap duties on cheap foreign goods.

"I'm happy with the outcome," Tobey said Friday upon learning of the ruling. "I'm happy they found what we said was true."

There's little doubt that the surge of foreign imports at unfairly low prices has undercut some of the expected benefits for American producers such as United States Steel Corp.

Fracking and other techniques to tap natural gas and oil have sharply boosted demand for steel tubes used for drilling and building pipelines, and that has led to steel tube imports from the nine countries topping $1.7 billion last year, a more than 31% jump from 2010.

South Korea has been by far the dominant shipper, with India, Vietnam and Turkey also showing substantial increases. The biggest dumping duty, 118%, would be levied on steel from Thailand, which had the smallest share of imports to the U.S. among the nine countries. The other affected countries are the Philippines, Saudi Arabia, Taiwan and Ukraine.

Korean tubular steel from Hyundai Hysco, a unit of the car company Hyundai, and another firm called Nexteel would be hit with dumping duties of 15.75% and 9.89%, respectively. These were a reversal from the Commerce Department's preliminary finding this year that no tariffs would be placed on South Korea.

The decision was cheered by domestic steel companies and the United Steelworkers union, which, along with some lawmakers, lobbied hard for penalties, particularly on South Korean steel. The U.S. industry has long accused South Korea and others of dumping steel in the U.S. at artificially low prices.

But Bank of America steel analyst Timna Tanners said it would take a tariff of at least 20% on Korean steel to have a meaningful effect, given the cost difference with U.S. producers.

What's more, a deeper look at the industry also tells the story of a U.S. steel market that is out of sync with the rest of the world, where steel prices have been declining as Chinese real estate construction has softened.

Despite an international oversupply, U.S. Steel and other domestic operators charge substantially more than global competitors for tubular goods. That's possible, analysts said, because the industry has gone through severe restructurings over the last few decades and is now more concentrated with greater ability to dictate prices.

Much of what's known as oil-country tubular goods are made from hot-rolled coil, which costs roughly $150 less a ton in parts of Asia than in the U.S., according to Charles Bradford of steel industry analysis firm Bradford Research in New York.

Worldwide, China is a leading producer and exporter of steel, but the country didn't figure into Friday's announcement because the U.S. already had levied big anti-dumping tariffs on its tubular steel goods in 2010, which nearly halted its imports in that category.

Some have speculated that South Korea could be selling steel sourced from China, but statistics from the International Trade Center in Geneva show that Korean purchases of such tubular goods from China represented just a fraction of the $818 million of Korean oil-country tubular steel shipments to the U.S. last year.

Officials at the South Korean Embassy in Washington and attorneys for Hysco and Nexteel did not answer requests for comment.

Roger Schagrin, a Washington lawyer for Boomerang, Energex Tube and other domestic steel makers, said that the tariffs on South Korean steel would provide "significant volume and price benefits for the U.S. industry."

The domestic industry will get a boost psychologically from the ruling and may go after other kinds of steel goods from big players such as China, said John Packard, publisher of Steel Market Update.

Yet U.S. steel companies have exacerbated the global glut with a huge — and some would say ill-advised — ramp-up in new mills and capabilities to produce these tubular goods for the energy industry. The result is that even with the tariffs, there probably still will be a long-term drop in prices that will put pressure on companies and workers alike.

"I've never seen this kind of expansion," said Bradford, who has been following the steel industry for nearly 50 years. "The amount of new capacity is just massive.... I think it's going to be a price war."

John Anton, a steel-industry expert at the research and consulting firm IHS, called the ruling a two-edged sword. Initially, it will be good for domestic steel producers, but not for companies drilling for oil and gas or for middlemen businesses in the U.S. distributing cheaper imported steel.

"If this goes into effect, I wouldn't be surprised if prices surged 10 to 15% almost immediately," he said, noting that it could ultimately be passed on to customers of gas. "It won't be a big shock to the system, but it won't be zero impact," Anton said.

The Commerce Department's tariffs will be imposed if the U.S. International Trade Commission, an independent federal agency, determines that domestic steel makers have been harmed by unfair trade practices.

Some analysts said that could be hard to prove because U.S. steel producers have continued to make handsome profits from sales of oil-country tubular goods.

But the ITC, in a preliminary decision, affirmed Friday that there is "reasonable indication" that the U.S. steel industry is being "materially injured" by imports of certain steel from Korea and four other countries. A final ruling is expected in mid-August.